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32 * @(#)fdesc_vfsops.c 8.4 (Berkeley) 1/21/94
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/filedesc.h>
44 #include <sys/kernel.h>
47 #include <sys/mutex.h>
48 #include <sys/malloc.h>
49 #include <sys/mount.h>
51 #include <sys/racct.h>
52 #include <sys/resourcevar.h>
53 #include <sys/vnode.h>
55 #include <fs/fdescfs/fdesc.h>
57 static MALLOC_DEFINE(M_FDESCMNT, "fdesc_mount", "FDESC mount structure");
59 static vfs_cmount_t fdesc_cmount;
60 static vfs_mount_t fdesc_mount;
61 static vfs_unmount_t fdesc_unmount;
62 static vfs_statfs_t fdesc_statfs;
63 static vfs_root_t fdesc_root;
66 * Compatibility shim for old mount(2) system call.
69 fdesc_cmount(struct mntarg *ma, void *data, uint64_t flags)
72 return kernel_mount(ma, flags);
76 * Mount the per-process file descriptors (/dev/fd)
79 fdesc_mount(struct mount *mp)
81 struct fdescmount *fmp;
82 struct thread *td = curthread;
86 if (!prison_allow(td->td_ucred, PR_ALLOW_MOUNT_FDESCFS))
92 if (mp->mnt_flag & (MNT_UPDATE | MNT_ROOTFS))
95 fmp = malloc(sizeof(struct fdescmount),
96 M_FDESCMNT, M_WAITOK); /* XXX */
99 * We need to initialize a few bits of our local mount point struct to
100 * avoid confusion in allocvp.
104 error = fdesc_allocvp(Froot, -1, FD_ROOT, mp, &rvp);
106 free(fmp, M_FDESCMNT);
111 rvp->v_vflag |= VV_ROOT;
114 /* XXX -- don't mark as local to work around fts() problems */
115 /*mp->mnt_flag |= MNT_LOCAL;*/
118 vfs_mountedfrom(mp, "fdescfs");
123 fdesc_unmount(struct mount *mp, int mntflags)
125 struct fdescmount *fmp;
130 if (mntflags & MNT_FORCE) {
131 /* The hash mutex protects the private mount flags. */
132 mtx_lock(&fdesc_hashmtx);
133 fmp->flags |= FMNT_UNMOUNTF;
134 mtx_unlock(&fdesc_hashmtx);
139 * Clear out buffer cache. I don't think we
140 * ever get anything cached at this level at the
141 * moment, but who knows...
143 * There is 1 extra root vnode reference corresponding
146 if ((error = vflush(mp, 1, flags, curthread)) != 0)
150 * Finally, throw away the fdescmount structure.
153 free(fmp, M_FDESCMNT);
158 fdesc_root(struct mount *mp, int flags, struct vnode **vpp)
163 * Return locked reference to root.
165 vp = VFSTOFDESC(mp)->f_root;
166 vget(vp, LK_EXCLUSIVE | LK_RETRY, curthread);
172 fdesc_statfs(struct mount *mp, struct statfs *sbp)
175 struct filedesc *fdp;
185 * Compute number of free file descriptors.
186 * [ Strange results will ensue if the open file
187 * limit is ever reduced below the current number
190 lim = lim_cur(td, RLIMIT_NOFILE);
191 fdp = td->td_proc->p_fd;
193 limit = racct_get_limit(td->td_proc, RACCT_NOFILE);
196 last = min(fdp->fd_nfiles, lim);
198 for (i = fdp->fd_freefile; i < last; i++)
199 if (fdp->fd_ofiles[i].fde_file == NULL)
203 * Adjust for the fact that the fdesc array may not
204 * have been fully allocated yet.
206 if (fdp->fd_nfiles < lim)
207 freefd += (lim - fdp->fd_nfiles);
208 FILEDESC_SUNLOCK(fdp);
211 sbp->f_bsize = DEV_BSIZE;
212 sbp->f_iosize = DEV_BSIZE;
213 sbp->f_blocks = 2; /* 1K to keep df happy */
216 sbp->f_files = lim + 1; /* Allow for "." */
217 sbp->f_ffree = freefd; /* See comments above */
221 static struct vfsops fdesc_vfsops = {
222 .vfs_cmount = fdesc_cmount,
223 .vfs_init = fdesc_init,
224 .vfs_mount = fdesc_mount,
225 .vfs_root = fdesc_root,
226 .vfs_statfs = fdesc_statfs,
227 .vfs_uninit = fdesc_uninit,
228 .vfs_unmount = fdesc_unmount,
231 VFS_SET(fdesc_vfsops, fdescfs, VFCF_SYNTHETIC | VFCF_JAIL);